Zdoom controller issue

For some reason I cant use the triggers together. I have it set up close to the PS3 Doom Classic Complete controls, with LT being Run and RT being shoot. The issue is that I cannot shoot while firing. Anyway to fix this?

Another thing, is there any way to map non-gameplay keys to the controller? I want to be able to press Start to bring up the main menu for example, and possibly assign quicksave/quickload to other buttons. My computer screen is cracked, so I have it hooked up to my TV, having to get up to save or pause is a pain..

EDIT: Forgot to mention, its an Xbox 360 controller with the Wireless Receiver